Sealing machine for the sealing of packages

ABSTRACT

A sealing machine for the sealing of packages comprises a sealing chamber in which packages can be sealed. The sealing chamber comprises a working platform on which packages can be conveyed; a chamber lid movable relative to the working platform between an open position and a closed position; a sealing mechanism for the sealing of packages; and a suction unit for suction of gas from a volume enclosed by the chamber lid and the working platform. The sealing machine further comprises a protective frame kinematically connected to the chamber lid, and the protective frame has apertures through which gas can flow from the outer space into the enclosed volume.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under 35 U.S.C. § 119(a)-(d) to German patent application number DE 10 2021 111 010.6, filed Apr. 29, 2021, which is incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a sealing machine for the sealing of packages according to claim 1 and to a method for the sealing of packages using a sealing machine according to claim 11.

BACKGROUND

Sealing machines are known from the prior art. They are typically used to seal either packages having a fixed shape or bags having a variable shape, each with the product filled inside. In this respect, the packages are typically made of plastic.

For this purpose, the sealing machines comprise a sealing chamber, which can be delimited, for example, by a working platform and a chamber lid, wherein a sealing mechanism is arranged in the sealing chamber, said sealing mechanism sealing the packages. This can typically be carried out by heating the (plastic) packages at the desired sealing points.

Conventional sealing machines comprise a suction unit for suction of gas, such as air, prior to the sealing of packages by the sealing mechanism, said gas being contained in the volume enclosed by the chamber lid and the working platform. Thus, it is ensured that the sealing of packages is carried out in the most sterile conditions available, which can increase the shelf life of the products wrapped inside the sealed packages.

Subsequently, the enclosed volume must be refilled with gas in order to convey the sealed packages out of the sealing machine and to feed in new packages to be sealed. During this process, the chamber lid also gets opened. The negative pressure prevailing in the enclosed volume requires a significant force for this purpose, which, due to said negative pressure, may result in delays when the chamber lid is lifted. Adding to this is the fact that the chamber lid is typically surrounded by a protective frame configured to prevent an operator from accidentally reaching into the chamber lid area.

As a result, due to the time required for ventilation, the capacity of the conventional sealing machines is limited.

SUMMARY

Based on the known prior art, the task to be solved is to provide a sealing machine and a method for the sealing of packages, capable of ensuring a high capacity of sealed packages, while at the same time securing the safety of the operators.

This task is solved by a sealing machine according to the disclosure or a method according to the disclosure.

The sealing machine for the sealing of packages according to the disclosure comprises a sealing chamber in which packages can be sealed, said sealing chamber comprising a working platform on which packages can be conveyed, a chamber lid movable relative to the working platform between an open and a closed position, a sealing mechanism for the sealing of packages, and a suction unit for suction of gas from a volume enclosed by the chamber lid and the working platform, wherein the sealing machine further comprises a protective frame kinematically connected to the chamber lid, and wherein the protective frame has apertures through which gas can flow from the outer space into the enclosed volume.

In this context, the kinematic connection of the protective frame to the chamber lid is to be understood as the protective frame essentially following the movement of the chamber lid. This can be achieved through either a suitable physical connection between the chamber lid and the protective frame, or by means of independent or coupled drive devices for the chamber lid and the protective frame. The protective frame substantially following the movement of the chamber lid can also be understood as deviating from the movement of the chamber lid. This relates, for example, to the timing of the movement of the chamber lid compared to the movement of the protective frame. In this way, the latter can either lag behind or precede the former in terms of time. Alternatively or additionally, there may occur differences in the motion sequence of the chamber lid and the protective frame. So, the protective frame can move (at least partially) in a different direction than the chamber lid or with a different (maximum) movement amplitude than the chamber lid.

Through the apertures disposed in the protective frame surrounding the chamber lid, gas from the outer space of the sealing machine (such as air) can selectively flow through the protective frame into the enclosed volume when, for example, the opening of the chamber lid has already been initiated. This allows pressure equalization to occur more quickly, while unwanted gas or air circulation can be avoided through the specific arrangement of apertures.

On the one hand, this accelerates pressure equalization and on the other hand, it ensures operator safety. In addition, the air flow is introduced in a controlled manner through these apertures, so that unintentional flying about of packaging residues can also be avoided.

In one embodiment, the apertures extend in an area above the working platform when the chamber lid is in the closed position and/or when the chamber lid is in the open position.

The area above the working platform can comprise, in particular, side surfaces or surfaces of the protective frame that are located directly above the working platform. Particularly advantageously, the side surfaces of the protective frame are provided with apertures that are substantially vertical on the working platform when the chamber lid is in the closed position. This ensures reliable air flow into an inner space or an enclosed volume.

Provision can be made for the protective frame to be kinematically coupled to the chamber lid so that the protective frame trails the movement of the chamber lid when the chamber lid is moved from a closed position to an open position.

The trailing of the protective frame prevents unintentional operator interference and at the same time, thanks to the apertures, ensures reliable ventilation of the enclosed space, even if the chamber lid is moved and the protective frame does not yet follow this movement.

In one embodiment, the sealing machine further comprises a shut-off mechanism for selectively opening and closing at least a portion of the apertures.

The apertures may, for example, be selectively closed by means of a shut-off mechanism in the form of a slide (for example, also driven by an electric motor) so as to prevent air flow through the protective frame when the packages are closed, thus ensuring sterile conditions as far as possible.

Provision can be made for the apertures to be configured such that a gas flow of at least 2 l/s or at least 5 l/s or at least 10 l/s or at least 15 l/s can flow from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.

By sizing the apertures to allow for gas flow, rapid ventilation can be ensured and thus pressure equalization between the enclosed space and the surroundings can be achieved quickly enough so that the chamber lid can be lifted reliably and quickly.

Furthermore, the total area of the apertures may be larger than the total area of other gas-permeable surfaces between the protective frame and the chamber lid. With this embodiment it is ensured that much of the air flow or gas flow occurs through the apertures themselves, rather than through other gas-permeable surfaces that cannot be avoided for manufacturing reasons, so that the air flow can be specifically controlled.

In one embodiment, provision is made for the protective frame to surround the chamber lid at least partially on all side surfaces coming into contact with the working platform in the closed position, or for the protective frame to surround all side surfaces of the chamber lid facing away from the volume enclosed in the closed position.

On the one hand, this allows the air flow to be controlled as advantageously as possible, and on the other hand, it prevents the operator from accidentally reaching into the chamber lid, which can further increase his safety.

The apertures can be arranged in one or more side surfaces of the protective frame extending transversely to a conveying direction of the packages in the working platform.

Viewed in the direction of conveying, these side surfaces of the protective frame can be the front and the rear of the protective frame. With this embodiment, air flow is achieved along or against the direction of conveying into the enclosed space, which may be advantageous in terms of supporting suction performance.

In particular, the sealing machine can be configured for sealing bags filled with product. Bags are to be understood here as such packages, which taken by themselves do not have a fixed predetermined shape.

The working platform may include a conveyor belt. With this embodiment, there is ensured reliable conveying of the packages, in particular when the packages are configured as bags.

The method for the sealing of packages by means of a sealing machine according to the disclosure, the sealing machine comprising a sealing chamber in which packages are sealed, the sealing chamber comprising a working platform on which the packages are conveyed, a chamber lid movable relative to the working platform between an open and a closed position, a sealing mechanism which seals packages, and a suction unit which sucks gas from a volume enclosed by the chamber lid and the working platform, wherein the sealing machine further comprises a protective frame kinematically connected to the chamber lid, and wherein the protective frame has apertures through which gas can at least temporarily flow from the outer space into the enclosed volume, comprising inserting at least one package into the sealing chamber with the chamber lid in the open position, moving the chamber lid into the closed position, suction of gas within the enclosed volume by the suction unit, sealing the at least one package with the sealing mechanism, and subsequently moving the chamber lid into the open position.

This method allows packages to be sealed under controlled conditions while achieving increased capacity.

In one embodiment of the method, the protective frame is kinematically coupled to the chamber lid so that the protective frame trails the movement of the chamber lid when the chamber lid is moved from a closed position to an open position. This embodiment ensures the safety of an operator.

Provision can be made that the sealing machine further comprises a shut-off mechanism for selectively opening and closing a portion of any or all of the apertures. This can be used to control the air flow and the amount of gas introduced. In particular, the shut-off mechanism can be configured as an automatic shut-off mechanism or as an automatically driven shut-off mechanism, which is driven, for example, via a suitable control unit and/or an electric drive.

Further, provision can be made that the portion of the apertures or all of the apertures is/are closed before gas is sucked within the closed volume, and that the portion of the apertures or all of the apertures is/are opened after at least one package is sealed and before the chamber lid is moved to the open position. This controls the gas flow and, in particular, the flow direction of gas flows entering the enclosed volume from the surroundings.

Provision can be made for a gas flow of at least 2 l/s or at least 5 l/s or at least 10 l/s or at least 15 l/s to flow through the apertures from the outer space into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.

This has a favorable effect on the suction performance in the enclosed volume and at the same time increases the achievable capacity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show an embodiment of a sealing machine;

FIGS. 2A and 2B show different embodiments of the protective frame; and

FIG. 3 shows a flow diagram of a method according to one embodiment.

DETAILED DESCRIPTION

FIG. 1A shows a sealing machine 100 according to one embodiment.

In the embodiment shown herein, the sealing machine 100 comprises an area referred to as a sealing chamber 110 in which a sealing of packages 130 with product 131 placed therein may occur. In particular, this packages can comprise food products, such as sausage products or cheese products. Preferably, the packages may be made of or comprise plastic. In this respect, the packages do not have to be rigid packages within the meaning of packages with a predetermined shape (for example, such as a packaging tray). Packages without a fixed shape, such as bags, are also included.

In order to carry out the sealing of the packages, the sealing chamber 110 comprises a working platform E on which the packages 130 are conveyed and which can extend not only in the region of the sealing chamber but also outside the sealing chamber, for example in the region of a conveyor belt 180 which can feed packages along the working platform in a conveying direction T to the sealing chamber. The working platform E can be configured as a conveyor belt so that the packages can also be conveyed within the sealing chamber. This can facilitate the positioning of the packages.

In the area of the conveyor belt, or at least before the packages are inserted into the sealing chamber 110, a cutter 181 may optionally be arranged to cut off excess portions of the package that for example may extend beyond the sealing chamber.

Additionally, the sealing chamber 110 comprises a chamber lid 101, shown in its open position in FIG. 1A.

The chamber lid 101 can be moved along the double arrow direction shown in the direction toward and away from the working platform E.

In one end position, the chamber lid is thereby in its closed position, in which it encloses, together with the working platform E, a volume, said volume being able to contain at least one package for the purpose of being sealed. In the other end position, the chamber lid is in the open position shown in FIG. 1A, so that packages 130 can be brought into the region of the sealing chamber, and/or packages that have already been sealed can be removed from the sealing chamber. For this purpose, there can be arranged, though need not be, another conveyor belt downstream of the sealing chamber 110, which can cause the onward conveying of the sealed packages.

The sealing machine preferably comprises further components described with reference to FIG. 1B, which may also be generally referred to as the sealing mechanism, to enable the packages to be sealed.

Further in FIG. 1A, there is illustrated a protective frame 102. According to the illustration in FIG. 1A, this at least partially surrounds the chamber lid 101.

In the embodiment shown herein, the protective frame 102 surrounds the chamber lid at least on a portion of the side surfaces of the chamber lid that are perpendicular to the working platform E. Provision can also be made that the protective frame 102 completely surrounds the chamber lid 101, except for the side of the chamber lid 101 facing the packages, since this side, as will further be described with reference to FIG. 1B, can effect the sealing of the packages jointly with any other components of the sealing chamber, or performs a function in that regard.

The protective frame 102 may be made of metal, in particular stainless steel, or may have an outer coating comprising stainless steel so that corrosion and, in particular, contamination by bacteria or the like can be avoided. Alternatively, the protective frame 102 may be made partially or entirely of Plexiglas or plastic, such that, for example, the protective frame is partially or entirely transparent. This makes it easier for the operator to follow the movement of the chamber lid even in the area of the protective frame, so that the risk of injury can be minimized.

According to the disclosure, the protective frame comprises a number of apertures 150 on at least one side surface, which preferably extends vertically to the working platform E.

These apertures 150 extend through the material of the protective frame 102, so that when the chamber lid 101 is in the closed position, a connection is established through the apertures between the outer space surrounding the sealing chamber 110 and the volume enclosed by the chamber lid and the working platform E, or at least the region of the chamber lid 101 lying within the protective frame.

This allows air flow into the volume enclosed by the chamber lid and the working platform E through the apertures 150 of the protective frame.

While seals can prevent air from entering when the chamber lid is closed, so that ambient air or gas does not enter the enclosed volume at least while the packages 130 are being sealed, the chamber lid is lifted again after the packages have been sealed to move the packages out of the enclosed volume or to insert new packages into the volume. Usually, the chamber lid is lifted before the pressure has been fully equalized.

Therefore, the chamber lid must at least partially be raised in the direction opposite to the ambient pressure, which is higher than the pressure prevailing in the enclosed volume. To achieve faster pressure equalization, the apertures 150 direct an air or gas flow in the area or volume at least partially enclosed by the chamber lid and the working platform E when the chamber lid is lifted, at least while the chamber lid is already lifted, so that pressure equalization occurs more quickly. In this way, forces opposing the lifting of the chamber lid can be minimized, which makes it possible to lift the chamber lid more quickly. This can advantageously increase the capacity of the sealing machine.

For this purpose, FIG. 1B shows a cross-section through the sealing chamber 110 along a plane perpendicular to the conveying direction T corresponding to FIG. 1A.

In the embodiment shown herein, there is apparent the region or enclosed volume V enclosed by the chamber lid 101 and the working platform E. The protective frame 102 is shown as surrounding the chamber lid 101 from the outside on at least one side surface shown herein.

The protective frame 102 and the chamber lid 101 may be driven by a common drive, such as an electric motor. Protective frame 102 and chamber lid 101 can preferably be offset from each other at least during movement of the chamber lid from the closed to the open position, so that protective frame 102 follows the movement of chamber lid 101. This prevents the operator from reaching directly under the chamber lid. Instead of a common drive, separate drives can also be provided for the movement of the protective frame 102 and the chamber lid 101, which are then controlled so that the trailing movement of the protective frame can be optionally implemented.

In the embodiment shown in FIG. 1B as an alternative to separate drives, it is provided that the protective frame 102 and the chamber lid 101 are connected via a driver 111 of the chamber lid, which can be moved in a guide 103 of the protective frame (according to the double arrow direction shown). In this case, it may be provided that only the chamber lid 101 is moved via a drive (not shown here) and that a movement of the protective frame 102 is indirectly effected via the chamber lid 101 by means of the driver.

In the lowered or closed position of the chamber lid 101, which is shown in FIG. 1B, the upper surface of the driver 111 has a distance h to the upper limit of the guide 103 of the protective frame. If the chamber lid 101 is now raised, the driver 111 runs along in the guide 103 of the protective frame and strikes the upper end of the guide 103 after a distance h. The upper surface of the driver 111 is then moved to the upper end of the guide 103. Starting from this point, the protective frame 102 is carried along with the chamber lid.

This means that, at least in the embodiment shown here, the protective frame 102 lags the movement of the chamber lid from the closed position to the open position (namely, according to the lag distance h). This ensures that an operator does not inadvertently reach into the area of the chamber lid, as this would require reaching under the protective frame 102 from below. At the same time, when the chamber lid is lowered into the closed position, this ensures that the protective frame initially rests on the working platform E and the chamber lid 101 does not reach this position until later (after the distance h has been covered further). Hereby, even when closing the chamber lid 101, an accidental intervention of an operator is detected and the downward movement then immediately stopped.

Advantageously, the distance h can be, for example, 5 cm to 10 cm. In this way, the protective frame is lowered early enough before the chamber lid reaches the working platform E so that the injury risk of operators is minimized to the greatest possible extent.

Nevertheless, this embodiment, in which the protective frame 102 trails the chamber lid 101, is not so mandatory.

Similarly, the follower and guide 103 can be interchanged so that the follower is arranged on protective frame 102 whereas the guide is arranged to move with chamber lid 101.

Preferably, other components are arranged in the inner space of the chamber lid 101 as part of the chamber lid and/or the sealing chamber 110.

Therefore, as part of the chamber lid and sealing chamber 110, optional seals 124 and 125 are shown that can isolate the enclosed volume V from the surroundings when the chamber lid 101 remains in the closed position, such that a negative pressure created by the suction unit 140 in the enclosed volume V can be maintained. The suction unit can be configured as a vacuum pump, for example, for the suction of gas (especially air) from the enclosed volume before the packages are sealed.

Further there is shown a sealing mechanism 120, which may be arranged to move along the double arrow direction shown, for example to seal a portion of the package 130 using a sealing die 123. For this purpose, the sealing die can heat the package so that the plastic material of the package melts in this area and thus, for example, film parts of a film bag that lie on top of each other are joined together, which achieves a sealing of the film bag. Furthermore, support members 121 and 122 can be provided which fix the package at least during sealing.

The connection between the chamber lid 101 and the protective frame 102 shown in the embodiment according to FIG. 1B is here only exemplary. Any kinematic connection between the protective frame 102 and the chamber lid 101 may be provided, wherein movement of the chamber lid 101 at least partially also occurs to movement of the protective frame 102 so that the protective frame substantially follows or at least trails the movement of the chamber lid.

In the embodiment shown in FIGS. 1A and 1 n FIG. 1B, the packages are shown as bags that are made of plastic or comprise plastic but are flexible in such a way that they do not have a fixed defined shape at room temperature. Alternatively or additionally, packages having a solid shape, for example in the form of packaging trays provided with a cover film in the sealing chamber, may also be sealed by the sealing machine 100. In such a case, provision can then be made for one or more trays to be arranged in the working platform E for receiving the packaging trays. In principle, these embodiments are known.

In FIG. 1B, the apertures in the protective frame 150 are not shown, but principally they may also be provided in the portion of the protective frame 102 shown herein.

FIGS. 2A and 2B show embodiments of the protective frame regardless of the chamber lid itself. At the same time, however, all embodiments already described with regard to the chamber lid in FIGS. 1A and 1B are provided as combinable with the embodiments described herein in FIGS. 2A and 2B.

In FIG. 2A, the protective frame comprises four side surfaces 221 to 224. All these side surfaces extend essentially vertically to the working platform E, although minor deviations from the vertical course of these side surfaces are included here, depending on the shape of the side surfaces and their positioning relative to the working platform. For example, the protective frame may include four side surfaces that together form a truncated cone (without a closed top surface and without a closed base surface), so that the individual side surfaces of this truncated cone are not exactly vertical on the working platform. Provision can also be made that only one, two or three of the side faces are not vertical on the working platform, but the remaining side face is.

While the protective frame in FIG. 2A as well as in the other embodiments is always described as having four side faces, the protective frame can also have more or fewer side faces (for example, three side faces or 5 side faces), depending on the configuration of the chamber lid or the intended use.

In the embodiment shown herein, it is provided that the side surface 221 and the side surface 222, which run perpendicular to the conveying direction T and are arranged transversely to the conveying direction, are provided with apertures 251 and 252, respectively. This causes air to flow in the direction of conveying or against the direction of conveying, which can be particularly advantageous with regard to any bag residues remaining within the enclosed volume. Alternatively, it may be provided that apertures are provided in only one side surface, such as side surface 221 or side surface 222.

Although it is not shown in FIG. 2A, it may further be provided that apertures 251 and 252 are also or alternatively arranged in one or both of the remaining side surfaces 223 and 224.

The configuration of the apertures is basically arbitrary. Nevertheless, from a manufacturing point of view, it may be preferable for the apertures to be arranged as holes or elongated holes in one or more rows.

In some embodiments, provision can be made that the total area of the apertures, or the total cross-sectional area of the apertures available for air flow, is greater than the area of all other gas-permeable surfaces between the protective frame and the chamber lid. For manufacturing reasons, absolute airtightness or gas tightness between the chamber lid and the working platform or the chamber lid and the protective frame cannot be achieved or would only be possible with a great deal of effort. This makes it difficult during operation of the sealing machine to avoid air flow even through these gas-permeable areas. However, if the total area of the apertures is selected to be larger than the total area of the other gas-permeable surfaces between the protective frame and the chamber lid, the gas flow can advantageously be controlled according to the ratio of the total areas so that a larger portion of the air flow can be directed through the apertures and thus specifically into the enclosed volume.

Preferably, the total area of the apertures is at least 1.1 times the total area of all other gas-permeable surfaces between the protective frame and the chamber lid. Particularly preferred is that the total area of the apertures can be 50% larger than the total area of the other gas-permeable surfaces between the protective frame and the chamber lid, and particularly preferred is that the total area of the apertures is twice as large as the total area of other gas-permeable surfaces between the protective frame and the chamber lid.

The size of the apertures and also the relative ratio to the total area of the other gas-permeable surfaces can be selected here depending not only on the desired guidance of the air flow, but also on how large the gas flow (in liters/second (l/s)) should be for a given pressure difference between the enclosed volume and the surroundings.

Thus, in certain embodiments, the total area of the apertures may be selected to provide a gas flow of at least 2 l/s or at least 5 l/s or at least 10 l/s or at least 15 l/s for a pressure difference between the exterior of the sealing machine and the enclosed volume of 0.1 bar. This gas flow depends on the flow rate, which in turn depends on the pressure difference, so that the area of the apertures to be provided can be selected depending on the desired process parameters.

This can be used, for example, to increase the speed at which the chamber lid can be lifted, so that the capacity can advantageously be increased.

In the embodiments described so far, the apertures had always been described as open areas of the protective frame. These can be, for example, holes, elongated holes or slots, which can be arranged in one or more rows parallel to each other or in any pattern. The disclosure is not limited in this respect.

However, it may be advantageous if the apertures can be selectively closed and opened, for example to prevent air or gas flow through the apertures when the chamber lid is closed, at least while sealing of the packages is taking place, so that undesirable entry of gases into the packages during sealing is prevented or the suction performance is not adversely affected by gas flowing in through the perforations.

In this respect, FIG. 2B shows an embodiment in which a shut-off mechanism 290 is provided to selectively open and close at least a portion of the apertures. The apertures are shown in the protective frame 202 here as the plurality of apertures 251. In the embodiment shown herein, the shut-off mechanism comprises a slider 291 that can be slid in front of the apertures (along the double-arrow direction shown), the slider in the embodiment shown herein being actuated, for example, by a drive (such as an electric motor) 292 that is connected to a controller 293 of the shut-off mechanism (such as a microprocessor or the like). The controller 293 and the drive 292 are shown here as part of the protective frame or as integrated therein. Such an arrangement is not mandatory. For example, the controller may also be configured as part of the control unit of the sealing machine and may be located outside the protective frame and connected to the drive 292 via suitable means for exchanging signals and or transmitting power, such as electricity, to the drive 292.

Preferably, the relative proportion of the apertures blocked by the slide 291 compared to the entirety of the apertures 251 can be adjusted, thereby also affecting the gas flow through the apertures. With this embodiment, it is not only possible to control the gas flow itself (i.e., in particular, the amount of gas flowing in), but also to control the direction in which this gas flow occurs.

In combination with the embodiment of FIG. 2A, for example, a corresponding shut-off mechanism for the apertures 251 and 252 (and/or a shut-off mechanism for further apertures possibly provided in the other side surfaces) may be provided for both the front side surface 221 and the rear side surface 222, said shut-off mechanisms preferably being operable independently of one another. Therefore, for example, only one of the shutoff mechanisms can be actuated to open or close perforations, or both can be actuated simultaneously, or depending on the gas flow to be achieved, one or both can be actuated to release some or all of the perforations.

Preferably, the slider 291 may have sealing elements that allow sealing of the apertures concealed behind the slider 291, wherein the sealing element may be arranged, for example, as a sealing lip 294 on the outer periphery of the slider 291 in the direction of the apertures 251 and may rest at least partially on the surface of the protective frame 202.

The sealing lip can be made of or comprise polyurethane, rubber or other flexible materials, in particular plastics.

FIG. 3 shows a flow diagram illustrating a method for the sealing of packages by means of a sealing machine according to one of the preceding embodiments.

The method begins at step 301, which comprises placing one or more packages into the sealing lid 110 according to FIG. 1A. Beforehand, the packages can be cut to size or protruding bag necks can be cut off, for example, by cutters 181 as shown in FIG. 1A. During step 301, the chamber lid does not remain in the closed position. Preferably, it is in the open position during the inserting of the packages.

After the number of packages has been positioned in the sealing chamber, or already during positioning of the packages in the sealing chamber, a movement of the chamber lid from the open position to the closed position may occur in step 302, so that the packages are enclosed in the volume enclosed by working platform E and the chamber lid after completion of this step. The protective frame is also moved together with the chamber lid. This can be moved synchronously with the chamber lid or trails its movement, as already described with reference to FIG. 1A.

Once the chamber lid is closed and therefore the volume in which the packages to be sealed are located is separated from the outer space, suction of gas inside the chamber lid can take place in step 303. This is typically the suction of air. If filling of the packages already takes place under a protective atmosphere, for example a nitrogen atmosphere, there occurs a suction of the corresponding gas, i.e. nitrogen. The method step 303 is not limited to the suction of a specific gas.

Once the gas has been sucked to a desired internal pressure in the enclosed volume and thus also removed from the packages, sealing of the packages can take place in step 304. If a plurality of packages are placed in the sealing chamber, all packages can be sealed simultaneously or individually one after the other or in groups.

After all packages have been sealed, the chamber lid is then returned to its open position in step 305, which involves ventilation of the enclosed volume until it has been vented to ambient pressure.

In this respect, the shut-off mechanism for the apertures can be actuated, in particular at the start of the movement of the chamber lid, if provided, in order to release the apertures, so that faster ventilation or faster pressure equalization can take place, even if the protective frame follows the movement of the chamber lid.

The packages can subsequently be removed from the sealing chamber and further packages can be inserted into the sealing chamber for sealing at the same time as or after a time delay, and the process is then repeated with step 301. 

What is claimed is:
 1. A sealing machine for sealing of packages, the sealing machine comprising a sealing chamber in which packages can be sealed, wherein the sealing chamber comprises a working platform on which packages can be conveyed; a chamber lid movable relative to the working platform between an open position and a closed position; a sealing mechanism for the sealing of packages; and a suction unit for suction of gas from a volume enclosed by the chamber lid and the working platform; wherein the sealing machine further comprises a protective frame kinematically connected to the chamber lid; and wherein the protective frame has apertures through which gas can flow from an outer space into the enclosed volume.
 2. The sealing machine according to claim 1, wherein the apertures extend in a region above the working platform when the chamber lid is in the closed position and/or when the chamber lid is in the open position.
 3. The sealing machine according to claim 1, wherein the protective frame is kinematically coupled to the chamber lid so that the protective frame trails the movement of the chamber lid when the chamber lid is moved from the closed position to the open position.
 4. The sealing machine according to claim 1, wherein the sealing machine further comprises a shut-off mechanism for selective opening and closing of at least one portion of the apertures.
 5. The sealing machine according to claim 1, wherein the apertures are configured such that a gas flow of at least 2 l/s can flow from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.
 6. The sealing machine according to claim 1, wherein the apertures are configured such that a gas flow of at least 5 l/s can flow from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.
 7. The sealing machine according to claim 1, wherein the apertures are configured such that a gas flow of at least 10 l/s can flow from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.
 8. The sealing machine according to claim 1, wherein the apertures are configured such that a gas flow of at least 15 l/s can flow from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.
 9. The sealing machine according to claim 1, wherein total area of the apertures is greater than total area of other gas-permeable surfaces between the protective frame and the chamber lid.
 10. The sealing machine according to claim 1, wherein the protective frame surrounds the chamber lid at least partially on all side surfaces coming into contact with the working platform in the closed position; or wherein the protective frame surrounds all side surfaces of the chamber lid facing away from the volume enclosed in the closed position.
 11. The sealing machine according to claim 1, wherein the apertures are arranged in side surfaces of the protective frame extending transversely to a conveying direction of the packages on the working platform.
 12. The sealing machine according to claim 1, wherein the sealing machine is configured for the sealing of packages formed as bags filled with products.
 13. The sealing machine according to claim 1, wherein the working platform comprises a conveyor belt.
 14. A method for sealing of packages by a sealing machine, the sealing machine comprising a sealing chamber in which packages are sealed, the sealing chamber comprising a working platform on which the packages are conveyed, a chamber lid movable relative to the working platform between an open position and a closed position, a sealing mechanism which seals packages, and a suction unit which sucks gas from a volume enclosed by the chamber lid and the working platform, wherein the sealing machine further comprises a protective frame kinematically connected to the chamber lid, and wherein the protective frame has apertures through which gas can at least temporarily flow from an outer space into the enclosed volume, wherein the method comprises inserting at least one package into the sealing chamber with the chamber lid in the open position, moving the chamber lid into the closed position, suctioning gas within the enclosed volume by the suction unit, sealing the at least one package with the sealing mechanism, and subsequently moving the chamber lid into the open position.
 15. The method according to claim 14, wherein the protective frame is kinematically coupled to the chamber lid so that the protective frame trails the movement of the chamber lid when the chamber lid is moved from the closed position to the open position.
 16. The method according to claim 14, wherein the sealing machine further comprises a shut-off mechanism for selectively opening and closing a portion of the apertures or all of the apertures.
 17. The method according to claim 16, wherein the portion of the apertures or all of the apertures is/are closed before gas is sucked within the enclosed volume, and the portion of the apertures or all of the apertures is/are opened after at least one package is sealed and before the chamber lid is moved to the open position.
 18. The method according to claim 14, wherein a gas flow of at least 2 l/s flows from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.
 19. The method according to claim 14, wherein a gas flow of at least 5 l/s flows from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less.
 20. The method according to claim 14, wherein a gas flow of at least 10 l/s flows from the outer space through the apertures into the enclosed volume at a pressure difference between the outer space and the enclosed volume of 0.1 bar or less. 